Preheat the oven to 350°For 180°C. Brush your tartpan with oil, then dust it with flour.
To a mixing bowl, add sugar, oil, water, lemonzest, and vanillaextract.Stir well with a spatula until the sugar and the oil are combined.
Combine flour and baking powder in a separate bowl, then add them to the wet ingredients.Mix with a spatula until the mixture turns into dough.
Compact the dough with your hands until all the pieces come together.
Take ¾ of the pastry dough and transfer it onto the tart pan.Flatten the dough with your hands until it covers the pan's bottom and sides.
Prick the bottom and the sides with a fork.This prevents air bubbles from cracking the crust.
Fill the base with the jam. Spread it out with the back of a spoon.Tip: if your jam is compact, stir it in a bowl first to break off lumps.
Dust a working surface with flour (you can use a cutting board) and roll the remaining dough with a rolling pin. Cut 8 - 10 strips with a sharp knife or a pastry wheel cutter.
Arrange five strips on top of the crostata, then arrange the other five strips diagonally to form a lattice top.Apply some pressure with your fingers where the strips and the edge of the tart meet so that they stick together.
Bake on a baking rack (not a baking sheet) in the center of the oven at 350°F or 180°C for 25 to 30 minutes, or until the crostata is golden brown.
Let cool down before removing from the tart pan. Slice and enjoy!